Railroads are typically constructed to include a pair of elongated, substantially parallel rails, which are coupled to a plurality of laterally extending ties. The ties are disposed on a ballast bed of hard particulate material such as gravel. Over time, normal wear and tear on the railroad may cause the rails to deviate from a desired geometric orientation.
Rail maintenance processes for addressing such concerns typically involve the use of a tamping machine with a buggy, which cooperate with each other to provide a three-point reference system to measure the position of the track prior to applying the desired corrections to the track. A typical correction process involves lifting rail with mechanical clamps, aligning the track by shifting it to a calculated position, and then tamping the ballast under each tie to hold the track in place. This work sequence is typically repeated at each tie during the course of the correction process.
Known reference systems often utilize light beams or lasers either alone or in combination with tensioned wires. In such systems, a buggy vehicle is equipped with a light source or laser projector, a shadow board extends from the rail maintenance vehicle, and a pair of receivers, each positioned over corresponding rail, are positioned at the rear of the tamping machine.
The reference points are used to establish a geometry of the track at the particular location being worked. That is, the recorded values are used to triangulate the geometry of the section of track being worked, while an onboard computer compares the previous section of track already corrected to the current section and makes the calculations for the required corrections to be made at the work heads. Similar recording and corrections are made with four point reference systems, i.e., the recorded geometry is calculated and corrected using different formulas that result in correction of the track to a desired position.
However, known reference systems are subject to a variety of outside influences and factors that may prevent the track from being returned to the desired geometric orientation, thereby reducing the efficiency of a railroad vehicle traveling along the track. For example, the receiver pairs may be tuned to search for a specific frequency of light that may be negatively affected by ambient light (i.e., sunlight) when the buggy vehicle is spaced apart from the rail maintenance vehicle. In addition, the tensioned wires may be affected by wind and weather, may become tangled or caught, and may be difficult to keep taut. Accordingly, an improved system for use in carrying out surfacing and/or lining operations on railroad tracks is desired.